The T2 chip is the flash storage controller. It is not talking to a soldered-on PCIe storage device, it is addressing the NAND directly. Apple theoretically co

The T2 chip is the flash storage controller. It is not talking to a soldered-on PCIe storage device, it is addressing the NAND directly. Apple theoretically could have a slot for NVMe separate from the system drive, but there is no industry standard for "card with NAND on it that the T2 chip understands".